A number of standardized supplementary services (e.g. CCBS) operate in the telecommunication network by using the TCAP end-to-end signalling capability, i.e. a direct relation between the originating and the destination entities of a call. These services establish the TC-dialogue by using a network address which, in particular cases, may identify a service (e.g. interaction with GVNS) or an incorrect geographical location of the remote user (e.g. number portability). Consequently, the end-to-end operation of the TCAP based service will fail either due to the lack of the service ASE or due to the absence of the addressed user at the addressed entity.
It is a first object of the present invention to provide a method and a system that permits a network operator to prevent the substantial number of service operation failures when the end-to-end TCAP based supplementary services realized at the peer entities, i.e. local exchanges, interact with other telecommunication services realized at an intermediate node, i.e. local or transit or gateway exchanges due to indirect addressing of the remote user.
It is a second object to provide a generic method which enables establishing of a relay link between an incoming TC-dialogue with an outgoing TC-dialogue at an intermediate node, resulting in a chain of end-to-end TC-dialogues between the originating local exchange node and the destination local exchange node.
It is a third object of the invention to offer the operator a transparent relay functionality without a need to deploy the TCAP based service ASE at intermediate nodes, and to provide a capability of differentiating the handling and the continuity of the chained dialogues based on the operation of involved telecommunication services.
It is a fourth object of the invention to provide a method for communicating the essential data elements between the physical entities, i.e. SSP and SCP, of an intermediate node based on intelligent network architecture for solving the said interaction, without deployment of the TCAP service ASE in all SSP nodes of a network. This communication method implies the facility of encapsulating the service ASE in a new TC-relay ASE being realized either as new operations within INAP or as another TCAP based supplementary service having own set of ASE data elements.
The invention is a method and a system in a telecommunication network for enabling a network operator to prevent service operation failure when there is an interaction between an end-to-end TCAP based supplementary service and an interfering telecommunication service. More particularly, it is the question of a case in which a subscriber connected to an originating local exchange node has requested activation of a supplementary service, being said TCAP based supplementary service, located in an application of said originating node. The supplementary service uses a Transaction Capability Application Part TCAP and a corresponding Abstract Service Element ASE for establishing an end-to-end Transaction Capability TC-dialogue, having a transaction ID, with the corresponding supplementary service in an application of a destination local exchange node to which an addressed remote subscriber is connected. The TC-dialogue terminates the request on a telecommunication service, being said interfering service, located in an application of an intermediate node.
The invention comprises means and steps for establishing a relay link between an incoming TC-dialogue and an outgoing TC-dialogue at the intermediate node for providing a chain of end-to-end TC-dialogues between the originating local exchange node and the destination local exchange node. A transparent relay functionality is used that is independent of utilizing the TCAP based supplementary service ASEs at intermediate nodes. The handling and continuity of the chained dialogues is differentiated based on the effect of the interaction caused by said interfering telecommunication service.
The transparent relay functionality communicates the TCAP based supplementary service ASE and said effect of the interaction between said incoming TC-dialogue, said interfering telecommunication service and said outgoing TC-dialogue.
The service ASE is encapsulated in a new TC-relay ASE that is realized either as new operations within Intelligent Network Application Part INAP or as another TCAP based supplementary service having an own set of ASE data elements.
Steps and means are provided for performing in the intermediate node, upon reception of an incoming TC-dialogue request related to a TCAP based supplementary service having a dedicated SubSystem Number SSN, and based on an analysis of the requested TCAP based supplementary service identity, as identified by a specific supplementary service Object IDentifier OID, and calling and called party address information sent together with the request, a number of essential interrelated measures.
A first one of these measures includes triggering of the transparent relay functionality in case either the OID is not recognized by the intermediate node, or the called party address information does not address a subscriber connected to the intermediate node.
A second measure initiates a TC-relay link procedure comprising preservation of the received TC-dialogue ID and sending of a query for number translation by communicating the called and calling party address information and the supplementary service ASE of the received TC-dialogue to the interfering telecommunication service.
A third measure includes analysing the received query and determinating by the interfering telecommunication service the new called party address information and the effect of the interaction with the TCAP based supplementary service as identified by the received OID.
In a fourth measure the TC-relay link procedure comprises establishing an outgoing TC-dialogue based on the received called party address information and the supplementary service ASE from the interfering telecommunication service. An association is built between the incoming and the outgoing TC-dialogues ID based on a received indication for handling of the TC-dialogue continuity.
For the step of differentiating the handling and continuity of the chained dialogues, there is provided an indication by the interfering telecommunication service on whether the TC-link relay functionality should use a Single Association Control Function SACF to establish a simple and single association between the incoming and the outgoing TC-dialogues, or a Multiple Association Control Function MACF to establish a multiple association using two SACFs between the incoming and the outgoing TC-dialogues.
Use of a SACF association is decided when the TCAP based supplementary service ASE used in the outgoing TC-dialogue is identical to the TCAP based supplementary service ASE received by the incoming TC-dialogue. Use of a MACF association is decided when the TCAP based supplementary service ASE used in the outgoing TC-dialogue is not identical to the TCAP based supplementary service ASE received by the incoming TC-dialogue.